Closed fluid-operated free-pump system with two parallel tubings within a third tubing



MarCh 18, 1952 c. J. coBERLY 2,589,572

CLOSED FLUID-OPERATED FREE-PUMP SYSTEM WITH TWO PARALLEL TUBINGS WITHINA THIRD TUBING Filed May 16, 1949 2 SHEETS-SHEET l coBE'RLY I OPERATEDFREE-PUMP SYSTEM WITH Two PARALLEL TUBINGS WITHIN A THIRD TUBING f/l//mm. viril/54755.. ?///f////// lllll CLOSED FLUID- March 18, 1952 FiledMay 16, 1949 Patented Mar. 18, 1952 CLOSED FLUID-OPERATED FREE -PUMPSYS- TEM WITH TWO PARALLEL TUBINGS WITHIN A THIRD TUBING Clarence J.Coberly, Los Angeles, Calif., assignor, by mesne assignments, to DresserEquipment Company, Cleveland, Ohio, a corporation of Ohio ApplicationMay 16, 1949, Serial No. 93,484

(Cl. S-46) 32 Claims. 1

My invention relates in general to tubing systems for fluid-operatedwell pumps and, more particularly, to a closed tubing system for afluid-operated well pump of the so-called free type. Reference is herebymade to my co-pending applications Serial No. 93,483, led May 16, 1949,Serial No. 93,482, filed May 16, 1949, and Serial No. 93,481, led May16, 1949.

It is conventional in the oil industry to employ a well pumpingapparatus which includes a free duid-operated pump, such a pump beingmovable into and out of the well through a tubing set in the well andbeing adapted to assume an operating position at the lower end of suchtubing. Examples of such duid-operated, free-pump systems are disclosedin my Patents Nos. 2,230,830, granted February 4, 1941, and 2,338,903Jgranted January 11, 1944.

In conventional duid-operated, free-pump systems, such as thosedisclosed in my aforementioned patents, two tubings are employed, onefor conveying operating iiuid downwardly in the well to the pump and theother for conveying iiuid produced by the well upwardly therein from thepump to the surface, the two tubings being referred to hereinafter asthe supply and production tubings, respectively. In such conventionalsystems, the pump is movable into its operating position through thesupply tubing. The supply and production tubings are interconnected attheir lower ends in uid communication with each other and with the wellso that the pump may receive operating fluid from the supply tubing andwell fluid from the well and so that it may discharge well fluid intothe production tubing as production fluid.

In installing such a free pump in the well, it is moved downwardlythrough the supply tubing into its operating position at the lower endthereof either by the action of gravity or by the application of fluidpressure to the upper end of the pump. After the pump has been installedin its operating position, operating fluid, which is usually clean crudeoil, is delivered to the motor section of the pump under relatively highpressure through the supply tubing. As is well known in the art, suchoperating iiuid is alternately directed by a suitable valve mechanism inthe motor section of the pump to opposite ends cf a motor piston whichis coupled to a pump piston in the pump section of the device, fluidfrom the 'well being admitted to the pump section by a suitable valvemechanism therein. Such alter- -nating application of operating fluidpressure to or repair, fluid pressure is applied to the lower u end ofthe pump to move it upwardly out of its operating position and throughthe supply tubing to the surface. This is accomplished conventionally byreversing the ilow through the system so that operating uid flowsdownwardly in the production tubing to the lower end of the pump andacts on the pump to move it upwardly through the supply tubing to thesurface.

In a conventional free-pump system of the foregoing character, the spentoperating uid discharged by the motor section of the pump is deliveredto the production tubing so that the spent operating fluid and theproduction fluid are intermixed and conveyed upwardly together throughthe production tubing. Since the operating fluid delivered to the pumpthrough the supply tubing must be clean, in order to prevent abrasionand corrosion of the moving parts ofthe pump, fresh operating fluid mustbe supplied to the system continuously. The continuous provision of suchfresh operating iiuid requires considerable surface equipment, normallyin the form of settling tanks or filters, which is expensive to installand operate. Also, in the particular arrangement hereinbefore mentionedwherein the pump is disposed in the supply tubing, the flow reversalnecessary to remove the pump from the well may carry any sand or otherforeign matter present in the production fluid into the supply tubingwith the result that such foreign matter may enter the motor section ofthe pump upon resumption of operation after reinstallation with theattendant possibility of damage to the pump. Y

In view of the foregoing, it is a primary object of this invention toprovide a closed system for the duid-operated, free pump which includesa third tubing separate from the supply and production tubings forreturning Vthe spent operating fluid to the surface independently of thewell fluid, the tubing for returning the spent -operating fluid beingreferred to hereinafter as the return tubing. With such a closed system,the spent operating iluid is separately conveyed back to the surface forstorage and re-use to actuate the fluid-operated pump so that there isvery little loss of operating fluid from the system and, consequently,the surface equipment necessary to supply fresh operating fluid to thesystem needs have only a relatively small capacity and can be relativelycheap and economical, both as regards initial cost and operating costs.Also, the reversed flow necessary to move the pump upwardly to thesurface during removal of the pump may take place through the returntubing to avoid carrying sand and other foreign matter into that portionof the system reserved for the operating fluid, which is an importantfeature. As will be pointed out in more detail hereinafter, furtherobjects of the invention reside in certain modifications of the pump andin the tubing arrangements employed to provide such a closed system.

Considering the invention more specically, an obgect thereof is toprovide a closed system for a fluid-operated, free pump comprisingsupply, return and production tubings which are set in the well and oneof which is adapted to receive the pump and to provide an operatingposition for the pump at its lower end, the supply, return andproduction tublngs respectively beingadapted to convey operating fluidfor actuating the pump downwardly into the well to the pump, spentoperating fluid discharged by the pump upwardly inthe well from the pumpto the surface and production fluid discharged by the pump upwardly inthe well from the pump to the surface.

An important object of the invention is to provide a closed systemwherein the supply, return and production tubings are set in the Wellwith two of the tubings disposed within the third. Another object inthis connection is to provide a closed system wherein the two innertubings are disposed side-by-side within the outer tubing. A furtherobject is to provide a closed system wherein one of the inner tubings isadapted to receive the pump.

Another object is to provide such a closed system wherein the threetubings are interconnected at their lower ends in fluid communicationwith each other and with the well so that the pump may, When in itsoperating position, receive operating 'uid for its actuation from thesupply `tubing through an intake, discharge spent operatingr fluidintothe return tubing through an exhaust, receive well fluid from the wellthrough `an inlet and discharge well fluid into the production tubingthrough an outlet.

Another object is to provide a closed system having means whereby adownward flow of fluid through one of the tubings, other than the tubinginrwhich the pump is disposed, may be applied i to the lower end of thepump to move it upwardly out of its operating position and through thetubing in which it is disposed to the surface whenever removal of thepump from the well is desired.

Another object is to provide a closed system which includes a tubularpump, receiver disposed at the lower end ,of and in alignment vwith thetubing through which the pump is movable, the pump receiver being, ineiect, an extension of such tubing and providing the aforementionedoperating position for the pump. A relatedobjectis to provide a-pumpreceiver having a seat at its lower end for the pump, the pump beingseated on such seat when itis in its operating position.

Another object is to provide a pump receiver 'having passages whichplace the interior thereof in fluid communication with the supply,return and production tubings and with the well in such a manner as toprovide fluid communication between the intake, exhaust, the inlet andthe outlet of the pump and the supply tubing, the return tubing, thewell andthe production tubing, respectively, when the pump is disposedin the pump receiver and seated on the pump seat.

Another object is to provide sealing means for normally preventingdirect flow between the tubings and the well by way of the pumpreceiverwhen the pump is in its operating position sothat operating fluid may'flow only from thesupply tubing through the motor section of the pump"to the-return tubing andy soi-that wellnuidmay flow only from the wellthrough the pump section of the pump to the production tubing. Morespecifically, an object in this connection is to provide a sealing meanswhich, when the pump is in its operating position, places the supplytubing in fluid communication with only the intake of the pump, thereturn tubing in fluid communication with only the exhaust of the pump,the well in fluid communication with only the inlet of the pump and theproduction tubing in iiuid communication with only the outlet of thepump. Another object is to provide a system wherein the aforementionedsealing means comprises annular sealing elements which are carried bythe pump adjacent various of the ports, such as the intake, exhaust,etc., therein and which are engageable with the inner wall of the pumpreceiver to prevent direct flow between the tubings.

Another object is to provide passage means communicating at one end withone of the .tubings, other than the tubing aligned with the pumpreceiver, and at its other end with a chamber in the pump receiverbetween the pump seat and the pump for applying a downward iiow of fluidthrough such tubing to the lower end df the pump to move it upwardly outof the pump receiver and to the surface.

Another object is to provide a sealing device for normally preventingflow of fluid between two of the tubings by way of the aforementionedpassage means and the pump receiver when the pump is in its operatingposition. Other objects in this connection are to provide a systemwherein the aforementioned sealing device is a springloaded valve in thepassage means and a system whereinV the sealing device is an annularsealing element adapted to be disposed between the pump and the pumpreceiver.

Another object is to provide a system wherein the tubing with which theaforementioned passage means communicates is the return tubing so thatthe pump may be moved upwardly to the surface by a downward flow ofclean uid through the return tubing to prevent introducing sand andother abrasive matter into the pump receiver.

Still another object is to provide a closed system wherein the pump ismovable into Yits operating position in the pump receiver through thesupply tubing and wherein the pump is movable upwardly to the surface bya downward flow of clean fluid through the return tubing so as to avoidcarrying any of the sand or other abrasive material which may be in thefluid in the production tubing into the pump receiver during thepump-removal operation. Y Another object is to provide a closed systemin which damage from any corrosive substances in the production fluid isminimized by permitting the production fluid to come in Contact withonly the Vproduction tubing. This is accomplished by locating theVsupply and return tubings without the production tubing, which is animportant feature.

Another object is to minimize the power required to overcome frictionbetween the production fluid moving upwardly through the productiontubing and the wall of the production tubing by employing a productiontubing having a large internal diameter. This feature is particularlyimportant under well conditions such that a pump having a motor sectionof small capacity and a pumpsection of large capacity may be employed.

.Another :object is :to maximize the external Ydiameter of the pump bymaking the tubing for tact of the production fluid to the productiontubing, i. e., by disposing the supply and return tubings without theproduction tubing.

Another object is to provide a closed system wherein the outer tubing isthe casing of the well.

'I'he foregoing objects and advantages of the present invention,together with other objects and advantages thereof which will becomeapparent, may be attained through the employment of the exemplaryembodiments of the invention which are illustrated in the accompanyingdrawings and which are described in detail hereinafter. Referring to thedrawings:

Fig. 1 is a utility View cf a closed, fluid-operated, free-pump systemwhich embodies the invention;

Fig. 2 is a horizontal sectional view taken along the broken line 2-2 ofFig. 1;

Fig. 3 is an enlarged, vertical sectional View taken along the brokenline 3--3 of Fig. 2;

Fig. 4 is a downward continuation of Fig. 3;

Fig. 5 is a fragmentary, vertical sectional view which is similar to thelower end of Fig. 3 but which discloses another embodiment of theinvention;

Fig. 6 is an enlarged downward continuation of Fig. 5 and is taken alongthe irregular broken line 6 5 of Fig. 7;

Fig. 7 is a horizontal sectional view taken along the broken line l-l ofFig. 6;

Fig. 8 is a fragmentary, vertical sectional view which is similar toFig. 5 but which discloses `still another embodiment of the invention:

Fig. 9 is a downward continuation of Fig. 8; Fig. 10 is a horizontalsectional view taken 5 along the broken line Iii-IS of Fig. 8;

Fig. 11 is a fragmentary, vertical sectional view which is similar toFigs. 6 and 9 but which discloses yet another embodiment of theinvention; and,

Fig. 12 is a horizontal sectional view taken along the broken line I2-I2of Fig. 11.

Considering the embodiment of the invention which is illustrated inFigs. 1 to 4 of the drawings and referring particularly to Fig. lthereof, the numeral I5 designates a well casing which is set in an oilwell and which is open below a packer I6 to an oil producing formationadjacent the Well as is well known in the art, the casing being providedwith a casing head Il at its upper end. That portion of the well casingI5 which is above the packer I 6 serves as a production tubing forconveying fluid produced by the well upwardly therein to the surface andwill be referred to hereinafter as the production tubing, rather thanthe well casing, for convenience. Set side-by-side within the productiontubing I5 and connected to the casing head I1 are supply and returntubings I8 and I9, the three tubings I5, I8 and I9 forming a closedsystem as will be discussed in more detail hereinafter. The supply,return and production tubings are interconnected at their lower ends influid communication with each other and with the well below the packerI3 by a tubular pump receiver which is aligned with and which, ineffect, forms a downward extension of the sup- -into the lower end ofthe supply tubing.

ply tubing I8. The pump receiver 20 provides an operating position for afree fluid-operated pump 2| which is movable downwardly through thesupply tubing into its operating position in the pump receiver, theinternal diameter of the pump receiver being substantially equal to thatof the supply tubing. As will be discussed in more detail hereinafter,the supply tubing I8 is adapted to convey operating fluid, such as cleancrude oil, under pressure downwardly in the well from the surface to thepump 2I to actuate the pump, the return tubing I9 is adapted to receivespent operating fluid discharged by the pump and to convey the spentoperating fluid upwardly in the well to the surface. The pump 2| isadapted to receive well fluid from the well below the packer I3 and todischarge into the production tubing I5 above the packer as productionfluid, the production tubing conveying theproduction fluid upwardly in-the well to the surface as previously indicated.

- The supply, return and production tubings are connected at their upperends to a pump head 29 having valve means (not shown) therein which isoperable from the surface by a handle 30 to direct flows of fluidthrough the tubings in the proper manner as will be discussed in moredetail hereinafter. The upper end of the production tubing I5 is shownconnected to the pump head 29 by a tube 3l. Also, connected to the pumphead 29 are production, supply and return lines 32, 33 and 34 which,during operation of the pump 2 I, are adapted to be connected Ain fluidcommunication with the production, supply and z return tubings I5, I8and I9, respectively, by the valve means in the pump head. Theproduction line 32 leads to a suitable point of disposal or storage forthe production' fluid, while the supply line 33 leads to a suitablesource (not shown) of operating fluid under pressure, which source maybe a conventional triplex pump having its intake connected to a suitablereservoir. The return line 34 leads to the reservoir for the source ofoperating fluid. As disclosed in my aforementioned Patent No. 2,338,903,the pump head 29 may also include a suitable pump catcher (not shown)for the pump 2l, the latter having at its upper end a tapered head 35which is receivable by the pump catcher during removal of the pump fromthe well.

Referring now to Figs. 3 and 4 of the drawings, the pump receiver 23 is,as previously indicated, aligned with and connected to the lower end ofthe supply tubing I8, the pump receiver having at its upper end a sleeve4I) which is threaded The lower end of the sleeve 4I) is threaded intothe upper end of the major bore 4I in an upper fitting 42 which formspart of the pump receiver 29, a sleeve 43 being threaded into the lowerend of the major bore 4I. sleeve 43 is threaded into the upper end of amajor bore 44 in a lower fitting 45 of the pump receiver 2i), an inletsleeve 46 communicating with the lower end of the major bore 44 andbeing welded or otherwise secured to the lower fitting., The inletsleeve 43 is provided with an off-set lower end which is connected tothe packer I6 and which communicates with the well below the packer sothat well fluid from below the packer may enter the pump receiver 2B byway of the inlet sleeve. I

The upper fitting 42 of the pump receiver 20 is provided with a minorbore 49 which is spaced from the major bore 4I therein and into whichThe lower end of the qth'e'lower. end of..the return tubing I9 isthreaded. The minorbore .49 communicates with the major bore "4| inthefitting 42 .through a rlateral passage .50in this tting and through aregistering port .5I in .a liner 52 which is pressed into the Imajorbore 4|. The lower vtting 45 Iof the pump receiver 29 is provided with aminor bore `54 which is. spaced from the major bore 44 therein landwhich communicates with the major bore `44 through a lateral passage 55,the lower iitting providing an annular chamber 56 which is adjacent thelower end of the pump 2| when the ,pump is in its operating position andwith which the lateral passage 55 communicates. Threaded .into the upperend of the minor bore 54 in the lower fitting 45 is a standing valve 5lwhich .permits iiow of production lfluid discharged by thepump-2| intothe production tubing I5 above .the packer i5, but which preventsreverse flow. `Itr'will be apparent that, with the foregoingconstruction, the pump receiver 25 interconnects the lower ends of theproduction, supply and return tubings I5, I8 and I9 in uidcommunicationwith each other and with the well below the packer I6.

The upper fitting 42 of the pump .receiver 20 Vis provided with apassage means 58 for applying a downward ow of fluid through the returntubing I9 to the lower end of the pump 2| to move the pump upwardly outof the pump receiver 2|) and through the supply tubing I8 to the surfacewhen removal of the Vpump is desired for any reason, this passage meanscomprising a longitudinal passage 59 which communicates at its upper.end with the minor bore 49 in the upper tting 42 and which communicatesat its lower end with a chamber St in this iitting. The passage means 53also includes a lateral passage 6| which connects the chamber 55 to anannular groove 62 in the upper fitting 42, this annular groovecommunicating with an annular space 63 between the pump 2| and theintermediate sleeve 43. The annular space 63 communicates at its lowerend with the annular chamber 56 at .the lower end of the pump 2|.Disposed in the chamber 60 is a spring-loaded VValve 64 which preventsiiow of Huid from the return tubing I9 `into the interior of the pumpreceiver 2t during .operation of the pump 2| and which is adapted toopen to permit such flow in response to downward flow of operating iiuidthrough the lreturn tubing I9 during removal of the pump from the well,as will be discussed'in more detail hereinafter. Y Y

Disposed in the lower end ofthe major bore 44 inthe lower fitting 45 andextending downwardly intov the inlet sleeve E is an inlet fitting l2which serves as a seat for the pump 2 I, the latter being in itsoperating position when it is disposed .in the pump receiver 2li andseated on the pump seat provided by the/inlet tting. The pump 2| isVadapted to seat on the inlet tting 72 automatically when it is moveddownwardly through the supply tubing into'the pump receiver 25xso thatit 'automatically assumes its operating position. The inlet tting I2also serves to convey fluid from the well to an inlet of the pump 2|when .the pump is in its operating position, the inlet fittingpreferably being provided with a check valve (not shown) therein whichpermits upward flow of well fluid into the interior of the pump receiver20, but which prevents downward ow of fluid out of the pump receiverinto the well. Theinlet iitting I2 is seated onan annular insert13,which is disposed in the Vmajor bore 44 and :which iislseated on, ashoulder 'I4 therein.

VExcept for certain modifications requiredto adapt it to the closedtubing system of .theginvention, the free fluid-operated pump-2| maya-beof conventional design and will not befconsidered in detail. In general,the pump 2| includes .a motor section having a pump section therebelow,the motor and pump sections respectively including coupled motor andpump pistons (not shown). rlhe motor section of the pump 2| is actuable.by operating iiuid under pressure delivered .thereto by the supplytubing I3, the operating fluid .under pressure being adapted to enterthe motorsection of the pump through ports which serve as an intake 'ISfor the pump and which are in fluid communication with the supply tubingwhen the pump is in its operating position. The ports of the intake 78are formed in an intake fitting 'i5 which carries the aforementioned.tapered head 35 and which isfconnected to the upper end of a tubularrod S5 extending upwardly .from the motor section of the pump 2|, therodbeing adapted to convey operating fluid under pressure from theintake to the motor section of the pump.

After the operating uid admitted to the motor section of the pump 2|through the intake I8 has actuated the pump, it is discharged from vvthemotor section through ports Vforming .an exhaust 8i of the pump. Whenthe pump 2| is inrits operating position, the Vexhaust 8| communicateswith an annular space 52 between thepump and the liners, the annularspace82 communicating with the return tubing I through the port5| Ainthe liner 52, the lateral passage 5E) inthe .upper fitting 4,2 and theminor bore 49 in this fitting. Thus, the operating fluid under pressurein the supply tubing I8 flows through the motorsection of the pump ZI toactuate it and isdis" charged into the return tubing I9 asspent-operating fluid.

n order to prevent direct flow of-operating fluid between theproduction, Supply .and return tubings i5, |18 and i9 by way of the`pump receiver 28 when the pump 2| is in its operating position, theclosed system under consideration is provided with a sealing meanscomprising annular sealing elements 85 and 8"! whichare carried by thepump 2l respectively above and below the exhaust 5I Yand which areadapted to engage the-liner 52 respectively above and below the port .5Itherein when the pump is in its operating position. Thus, the annularsealing elements-.'85 :and =81 isolate the intake 'i8 and the exhaust:8| `when the pump 2| is in its operating positionso that ie intake maycolfnrnunieate only with -tliesupply tubing I8 and so that the exhaustmaycommunicate yonly with the return vtubing I5. vAs previouslyindicated, flow between the return tubing I 9 and the production tubing1.5 Abywayof the passage means 58 during operation ,of the pump .2l isprevented by .the spring-loaded valve 64.

As previously indicated, the pump Vsection of the pump 2| is providedwith aninletatitslower end through which well fluid is adapted toenterthe pump section by w-ay of the inlet n-tting .212, the pump sectioninlet not being shownspecically. The pump section 4of :the pump is valsoprovided with ports forming .an outletSS orlthe production uiddischarged bythepump section, the outlet-communicating .withthe annular.space 53 between the pump 2| and the intermediate sleevefi when the pumpisin its operatingposition. Thus, production fluid discharged by Ythepump section of the pump .2| through Athe outlet 9 88 flows downwardlythrough the annular space 63 into the annular chamber 59 and flows fromthis chamber into the production tubing I above the packer I6 by way ofthe lateral passage 55 in the lower tting 45, the minor bore 54 thereinand the working valve 51.

It will be noted that the annular sealing element 81 is disposed betweenthe exhaust 8| and the outlet 88 so that it p'revents flow between thereturn and production tubings I 9 and I5 when the pump is in itsoperating position. Also, since the pump 2| is seated on the inletfitting 12 when in its operating position, the pump seat provided by theinlet fitting serves to prevent direct now between the well and theproduction tubing I5.

Considering the operation of the embodiment illustrated in Figs. 1 to 4of the drawings, it will be assumed that the pump 2| is in operation topump fluidfrom the well upwardly through the production tubing I5 to thesurface. Under such conditions, the pump 2| is in its operating positionin the pump receiver 29 wherein it is seated on the inlet tting 12, andthe aforementioned valve means in the pump head 29 respectively connectsthe supply, return and production tub-- ings I8, I9 and I5 to thesupply, return and production lines 33, 34 and 32. Thus, operating liuidunder pressure is conveyed downwardly to the pump 2| through the supplytubing I 8 and enters the motor section of the pump through the intake18 to actuate the pump, spent operating fluid being discharged into thereturn tubing through the exhaust 8| and being conveyed upwardly in thewell to the surface by the return tubing. The well fluid entering thepump 2| through its inlet is discharged into the production tubing I5through the outlet 88 and is conveyed upwardly in the well to thesurface as production fluid. It will be apparent that, with thisconstruction, the spent operating fluid is returned to the surfaceseparately from the production fluid so that it may be re-used toactuate the pump 2| which is a primary feature of the invention.

In the event that removal of the pump 2| from the well is necessary inorder to service or repair the pump, or for any other reason, it ismerely necessary for the operator to set the handle 3l) controlling thevalve means in the pump head 29 in a position such that the valve meansconnects the supply line 33 to the return tubing I9 so that theoperating fluid under pressure flows downwardly into the well throughthe return tubing. Preferably, the valve means also connects 'the supplytubing I8 to the return line 34 under such conditions, and preventsiluid communication between the production tubing I5 and the productionline 32. Alternatively, fluid flow through the production tubing I5 andthe production line 32 may be prevented by closing a valve 94 in theproduction line.

Under the conditions outlined in the preceding paragraph, operatingfluid under pressure ows downwardly through the return tubing I9 andinto the annular chamber 56 at the lower end of the pump 2| by way ofthe minor bore 49 in the upper fitting 42, the passage means 58 and thel0 pressure of the operating fluid entering thev annular chamber 56 inthe foregoing manner is applied to an annular area 95 at the lower endof the pump 2| so as to unseat the pump from the inlet fitting 12 and isthen applied'to the entire area of the pumpv so as to move it upwardlyin the pump receiver 20, upward flow of the operating fluid applied tothe lower end of the pump in this manner past the pum'p being preventedby the annular sealing elements 85 and 81. After the pump 2| has movedupwardly in the pump receiver 29 a distance such that the annular seal-`ing elements 3S and 81 disengage the liner 52,

upward flow of operating fluid past the pump is prevented by packingdevices 9B and 91 which are carried by the rod and which are adapted toengage the inner wall of the supply tubing I8 in a substantiallyHuid-tight manner, the portions of the pump 2| which carry the annularsealing elements 86 and 91 preferably being of smaller diameter than theinternal diameter of the supplyA tubing so as to prevent damage to thesealing elements during movement of the pump through the supply tubing.After the pump has cleared the port 5| in the liner 52, the downward owof operating fluid through the return tubing I9 is applied to the lowerend of the pump to move it upwardly directly through the lateral passage50 and the port 5|. Thus,y the operating fluid under pressure owsthrough the passage means 58 to unseat the pump 2| and to move itupwardly in the pump receiver 20 a sufficient distance to clear the port5I. Thereafter, the downward flow of operating fluid under pressurethrough the return tubing I9 enters the pump receiver 2|] through thelateral passage 59 and the port 5| to move the pump upwardly out of thepump receiverv andl through the supply tubing to the surface.

During the foregoing operation of removing the` pump, now of operatingfluid out of the pump receiver into the well is prevented by the checkvalve in the inlet tting 12 and ow thereof in to the production tubingI5 is prevented because flow through the production tubing is prevented,as by closing the aforementioned valve 94, or by means of the valvemeans in the pump head 29.` It will be noted that, since the standingvalve 51 prevents downward ow of production fluid out of the productiontubing I5 and into the pump receiver, none of the production fluid canenter the pump receiver during the pump-removal operation,` which is animportant feature since it prevents sand and other foreign matter whichmay be in the production fluid from entering the pump receiver. Thiseliminates any possibility of foreign matter of this nature entering themotor section of the pump upon re-installation thereof. It will be notedthat, under the conditions hereinbefore outlined, the operating fluid inthe supply tubing I8 above the pump 2| is returned to the reservoirthrough the return line 34 during the pump-removal operation so thatsubstantially none of the operating fluid is lost from the system. Whenre-installation of the pump 2|, or of a replacement pump 2|, is desired,the pump to be installed is inserted into the upper end of the supplytubing IB through the pump head 29. The

operator then sets the handle 39 controlling the Valve means in the pumphead in a position such that the supply tubing is placed in fluidcommunication with the supp-ly line 93 and the return tubing I9 isplaced in fluid communication with the return line 34. Thus, theoperating fluid under pressure entering the system through the supplyline 33 acts on the upper end of the pump 2| to Vmove it'. downwardly'through; the: supply tubing and' into .its operating'position'in thepumpv receiver wherein itlis seated on theinletttlng T2, the operatinguid previously introducedbelow the pump during the pumperemovaloperation being; displaced upwardly through the-returntubing. I9 andintothe return line 34 leading tothe. reservoir. During the operation of4installing the pump', the' valve 913, or4 the valve means in the pumphead 29, preferably -prevents flow'through the production tubing |5l andthel production lineV 32 so that -all of the iuidv employed'. during thepumperemoval operation is returned. tothe reservoir duringre-installation of'tl'epump. However, itwill be understood that iftle;operatingfluid in the supply tubing-has become contaminated' priorto re-installation of the pump 2| for any reason, returning suchcontaminated operating. fluid to'. the reservoir' may beavoided bypreventingfluid flow through thel return tubing I9' and by permittingfluid ilow throughthe production tubing I5.

As.will`be apparent, one advantage of ther embodiment' hereinbeforedisclosed is that it is possible. t'o remove and re'instal1 the pump 2|with substantially noV loss of Voperatingfiuicl from the system,thelproduction tubing |51 being'isolated from tliat'zportion' of thesystem' reserved for the operating uid during' the" operationsofremovingLand/.re-inst'alling v'the pump;

It'willalso .be notedthat the embodiment previously disclosed permitsthe use of a production tubing |of relatively large diameter tominimizeiriction losses between the production fiuid stream. and theproduction tubing,` which is an important. feature, particularly inwells permitting tlieuse. of ia pump having a pump section oi largecapacity and. a motor section of small capacity, .Since itpermits a highratioof production to power. input'.

A'nother advantage ofthe embodiment of Figs. 1.to.4` is thatthe'production'fluid flowing through the. annular chamber 'constantlywashes away any sand'deposits tending to form at the j unction ofthepumps 2| andthe inlet fitting i2 to keep thepump seat free.

The embodiment of my invention which is illustrated in Figs. 5 to 7 ofthe drawings is similar to that illustrated in Figs. 1 to 4 and can bestbe describedv by pointin'g'out the difference between it'andftlfe"embodimentv of Figs. l. to 4i, identical reference numeralsbeing employed for correspending, components.v One difference betweenthe embodiment presently underv consideration and thaticonsideredpreviously isY that'the lateral passage 55 in the lowerfitting e5 forthe production fluid communicates directly with the annularspacef63-between the pump 2| and the intermediate sleeve 43, instead of'with the annular chamber. 5'6. atthelower end of the pump. When thepump. 2`| is in its operating positiointhe annular space 63. isseparated from the annular chamber 56Y by an annular sealing element ISIwhich is carried by the pump 2| adjacent its lower end and which isadapted to engage a liner 02 pressed into the major bore 44 in the lowerfitting. .As-Will be apparent in the light of the neXt paragraph, t-helannular sealing element |i| thus prevents fluid communication betweenthe production tubing |5-and the return tubing i9 when the pump 2 listinits operating position.

The :only other. difference between the two embodiments-disclosedin'Figs. 5 to '7 of the drawings residesin the passage means 58, thepassage means 58 ofthe embodiment of Figs. 5 to 7 lncluding'a tubeHit'whichis'threaded at its upperend into a bore |64 communicatingwith-the minorbore' 59 in the upper fitting 42. The tube H13 isYthreaded at' its lower end into the upper end of a bore m5 which isspaced from the major bore M in the lower tting't of" the pump receiver2d, thepbore lcommunicating-with the annular chamber. 5b at" the lowerend ofl the pump 2| through' radial' passages |06, anl annular groove|61 andalateralpa'ssage` G8 in the lower fitting. In practice, insteadof forming the bore |65 directly in the lower fitting 5, I prefer toform this bore, the lateral passage lS and the groove |91 in an insertIBS which is disposed in a minor'bore lll) formed in the lower tting`proper, the tube |03 beingthreadedly connected to this insert and' Figs.5Y to '7 of the-drawings when'the pump 2| is incperati'on is-identicaltoV that of the embodimentof Figs. l'to 4, except thatVthe'annularsealing elementv lili prevents flow between the productionand return tubings l5 andY |9, this func:-

tion being'performed' by the spring-loaded valve Gli in the previouslydisclosed embodiment. The operation is also identical during thepump-removal operation except that the flow of operating fluid underpressure from the retiun tubing i9 to the annular chamber 56-does nottakeplace through any spring-loadedvalve. The operation of theembodiment in Figs. 5 to 7 during reinstallation -off the pump 2| isalso identical to thatof the embodiment or" Figs 1 to 4.

Turning now to the embodiment of the invention which is illustratediii-Figs. 8 to 10 of the drawings, I show a closed tubing system whichis set in a well (not shown) and which includes supply, return andproduction tubings respectively designated bythe numerals il, H3 and H9,the supply and production tubings being set side-byside within thereturn tubing i8. As isthe case with theproduction tubingl I5, thereturn tubing H3' may, if desired, be the casing of the well, in whichcase it isf necessary to employ a packer (not shown) such as the packerl5. The supply. return and'production tubings' Hl; |28 and ||9 areinterconnected at their lower ends in fluid communication with eachother and with the well by a tubular pump receiver |22) which is alignedwith and which, in eiect. forms a down ward extension of the supplytubing. The pump receiver |29 provides an operating position for thefreefluid-operated pump 2 I, which is movable downwardly through the supplytubing into its operating position in the pump receiver, the internaldiameter of the pump receiver being substantially equal to that of thesupply tubing. As in the previously discussed embodiments, the supplytubing is adapted to convey operating fluid under pressure downwardly inthe well to the pump 2| to actuate the pump, and the return tubing ||8is adapted tol convey. spent operating fluid discharged by the pumpupwardly in the well to the surface. The pump 2| is adapted to receivewell uid from the well and to discharge it intothe. production tubing l||9 and the production fluid, the production iiuid thenflowing upwardlythrough the production tubing to the surface.

As best shown in Figs. 8 and 9 of the drawings,

the lower end of the supply tubing l |'l is threaded into a tubularcoupling |42 into the lower end of which is threaded a sleeve |43, thelower end of this sleeve being threaded into the upper end of a majorbore 44 in a fitting |45 which forms part of the pump receiver |20.Communicating with the lower end of the maior bore I4 and suitablysecured, as by welding, to the fitting |45 is an inlet sleeve |46, asuitable packer (not shown), such as the packer I6, being connected tothe inlet sleeve |46 in the event that the return tubing 8 forms thecasing of the well.

The return tubing ||8 communicates with the interior of the pumpreceiver |20 through radial ports |48 in the coupling |42 and throughregistering ports |49 in a liner |5|J pressed into the coupling |42. Thetting |45 is provided with a minor bore |5| therein which is spaced fromthe major bore |44 and into which the lower end of the production tubingl is threaded, the minor bore communicating at its lower end with anannular chamber |52 at the lower end of the pump 2| through a lateralpassage |53 in the tting |45. Disposed in the minor bore |5| is astanding Valve |54 having spring ngers |55 which are adapted to engageshoulders |50 to hold it in place, the valve having an inside speartting |5'i for the reception of a suitable tool lowered through theproduction tubing I IQ to remove the valve, as is well known in the art.The valve |54 is adapted to permit upward flow of production uid intothe production tubing i9, but prevents' reverse flow.

The embodiment presently under consideration is provided with a passagemeans |58 for applying a downward ow of fluid through the return tubing8 to the lower end of the pump 2| to unseat the -pump and move itupwardly out of the pump receiver |20 when removal of the pump isdesired for any reason, this passage means including a passage |59 whichcommunicates at one end with a chamber |60 in the fitting |45 and at itsother end with the minor bore |5| in this tting. The chamber |60contains a spring-loaded valve I6! which prevents flow through thepassage means |58 from the return tubing ||8 into the annular chamber|52 by way of the minor bore I5! and the lateral passage |53 when thepump 2| is in operation so that the pressure in the return tubing isthat of the spent operating fluid. However, the spring-loaded valve |6|is adapted to open in response to a' downward ilow of operating fluidthrough the return tubing 8 to permit such o perating fluid to enter theannular chamber |52 to act on the lower end of the pump 2|.

Disposed in the lower end of the major bore |44 in the iitting |45 andextending downwardly into the inlet sleeve |46 is an inlet ntting |12for the pump 2|, the inlet of the latter being adapted to receive welliiuid from the well through the inlet tting when the pump is in itsoperating position. As is well known in the art, the inlet fitting |72is provided with a check valve (not shown) therein which permits upwardflow of well iiuid into the interior of the pump receiver |20, but whichprevents downward flow of fluid out of the -pump receiver into the well.The inlet fitting |'|2 is seated on an annular insert |'|3 which isdisposed in the major bore |44 in the fitting |45 and which is seated ona shoulder |'|4 therein.

As in the previously discussed embodiments, the inlet fitting |12 alsoserves as a seat for the pump 2|, the latter being in its operatingposition when it is disposed in the pump receiver |20 14 and seated onthe pump seat provided by the inlet fitting. The pump 2| is adapted toseat on the inlet tting |l'2 automatically when it is moved downwardlythrough the supply tubing into the pump receiver |20 so that itautomatically assumes its operating position.

When the pump 2| is in its operating position, the operating uid underpressure conveyed downwardly through the supply tubing enters the motorsection of the pump through the intake 78 and the tubular rod 80 and isdischarged from the motor section of the pump through the exhaust 8| asspent operating fluid. It will be noted that the exhaust 8| communicateswith an annular space |82 between the pump |2| and the liner |50, thisannular spacecommunicating with the return tubing I i8 through the ports|43 and |49. Thus, the operating uid under pressure in the supply tubing||'I flows through the motor section of the pump 2| to actuate it and isdischarged into the return tubing ||8 as spent operating fluid.

It will be noted that the annular sealing elements 8E and 8? arerespectively located above 4 and below the ports |49 in the liner |50 sothat the production tubing H0, the exhaust 88 comlmunicating directlywith an annular space |83 between the pump 2| and the sleeve |43. Thisannular space communicates at its lower end with the annular chamber|52.

The operation of the embodiment presently under consideration duringoperation of the pump 2| is substantially to that of the embodiment ofFigs. 1 to 4 of the drawings and it is thought that a detaileddescription is unnecessary. During removal, of the pump 2| from thewell, operating iiuid is caused to flow downwardly through the returntubing H8, which causes the springleaded valve i5| to open to permitsuch operating iuid to act on the annular area 95 at the lower end ofthe pump. This unseats the pump and causes it to move upwardly in thepump receiver |20, the pressure of the operating iiuid flowingdownwardly through the return tubing being applied to the entire area ofthe pump once it has unseated. After the pump 2| has cleared the ports|48 and 54S, the operating fluid flowing downwardly through the returntubing may enter the pump receiver |20 below the pump through suchports, instead of through the springloaded valve IBI. As before, acontinued downward. ow of operating iiuid through the return tubing H8results in upward movement of the pump 2| through the supply tubing tothe surface. The pump 2| may be re-installed in substantially the samemanner as in the embodiments of Figs. 1 to 4 of the drawings.

It will be noted, that, as in the case of the previously describedembodiments, the operations of removing and re-installing the pump 2|may be performed with substantially no loss of operating fluid from thesystem, which is an important feature. production tubing i I9 cannotreturn to the pump receiver |20 past the standing valve |54, no sand orother foreign matter in the production iiuid Also, since the productionfluid in the' canenten the pump receiver during the operations ofremoving and re-installing the pump.

Another advantage of the embodiments of Figs. 8;to. 10 isvthat paraincontrol issimplified and corrosion'damagefis restricted tothe'production tubing ||9 because of the fact that the production fluidcomes in contact with only the production-tubing.

Still anotheradvantage is that the flow of production fluid through theannular chamber |52 prevents sand deposits from covering the pump seatin the inlet fitting |72.

The embodiment of Figs. l1 to l2 is similar to that of Figs. 8 to l0 andidentical numerals have been employed to designate correspondingcomponents. The only difference between the embodiment presently underconsideration and that illustrated in Figs. 8 to 10 isv that thespringloaded valve ll is eliminated, the passage means |58l merely beinga port 26| formed in the fitting |65 to providefluid communicationbetween the return tubing ||8 and the annular chamber |52 at the lowerend of the pump |2|. Instead of communicating with the annular chamberthe-lateral passage |53 in the tting |65 communicates with an annular'space 232 which is located below and communicates with the annular space|83 into which the production fluid is discharged through the outlet 8Sof the pump 2|. In order to separate the return and production Vtubings||8 and i9 so that no ilow can take place therebetween by way of thepassage means |53 when the pump 2| is in its operating position, thepump is provided with an annular sealing, element 203 which is adaptedto engage a liner 204 pressed into the major bore Idil in the fitting|45.

` The operation of the embodiment of Figs. ll and l2 is substantiallyidentical to that of the embodiment of Figs. 8 to l0 and ardetaileddescription is thought to be unnecessary.

Although I'have disclosed several exemplary embodiments of the inventionfor purposes of illustration, it will be understood that I do not intendto be limited specifically thereto since various changes, modiiicationsand substitutions may be" incorporated in such embodiments withoutdeparting from the spirit of the invention.

I claim as my invention:

1. In a closed, fluid-operated, free-pump system for a well, thecombination of: supply, return, and production tubingsset in the welland respectively adapted to convey operating fluid downwardly into thewell from the surface, spent operating fluid upwardly in the well to thesurface and fluid produced by the well upwardly therein to the surface,two of said tubings being inner tubings disposed within the third; meansfor interconnecting the lower ends of said tubings in fluidcommunication with each other and with the well; and a fluid-operated,free pump movable in one of said inner tubings into an operatingposition at the lower end thereof, said pump having an intake, anexhaust, an inlet andan outlet which communicate with said supplytubing, said return tubing, the well and said production tubing,respectively, when said pump is'in said operating position.

2. In a closed, fluid-operated, free-pump system for a well, thecombination of three tubings set inthe well and respectively adapted toconvey operating, fluid downwardly to the well from thesurface, spentoperating fluid upwardly in theiwell to the :surface and fluid producedby the welll upwardly therein to, the surface, two of.

said tubings being-innertubings disposed withink each other and with thewell; a pump seat at the lower end of and aligned with Vone of saidinner tubings; and a fluid-operated, free pump. movable in said oneinner tubing into an operating position at the lower end thereof whereinit is seated on said pump seat, said pump having, an intake, an exhaust.and an outlet which communicate with said tubings, respectively,Y whensaid pump is in its operating position, and having an inlet whichcommunicates with .the well when said pump is in said operatingposition. v

3. In a closed, Vfluid-operated, free-pump system for a well, thecombination of supply, return and production tubings set inthe well andrespectively adapted to convey operating fluid downwardly into the Wellfrom the surface, spent operating fluid upwardly in the well to thesurface and fluid produced by the well upwardly therein to the surface,two of said tubings being inner tubings disposedwithin the third;atubular pump receiver at the lower end of andaligned with one of saidinner tubings, said pump receiver being connected to the lower ends ofsaid tubings in'fluid communication therewith and being in fluidcommunication with the well; and a fluid-operated, free pump movable in,said one inner tubing and movable into anoperating posi.- tion in saidpump receiver, said pump having an intake, an exhaust, an inlet and anoutlet which communicate with said supply tubing, saidreturn tubing, thewell and said production tubing, respectively, when said pump is in saidoperating position.

4. A closed system as set forth in claim 3 including sealing devices fornormally preventing direct flow of uid between said tubings and the wellwhen said pump is in said operatingposition.

5. In a closed, fluid-operated, free-pump system for a well, thecombination of supplyre turn and production tubings set in the well andrespectively adapted to convey operating fluid downwardly into the wellfrom the surface, spent operating fluid upwardly in the well to thesur-v face and fluid produced by the well upwardly therein to thesurface, two of said tubings being inner tubings disposed within thethird; a tubular` pump receiver connected to the lower ends of saidtubings in alignment with one of said inner tubings, said pump receivercommunicating at its upper end with said one inner tubing and havingsubstantially the same internal diameter as said one inner tubing, andsaid pump receiver having passages which provide fluid communicationbetween the other of said inner tubings and said pump receiver, betweenthe'outer of said tubings and said pump receiver and between the welland said pump receiver; a pump seat carried by said pump receiver at thelower end thereof and in alignment therewith; a fluidoperated, freepiunp movable in said one inner tubing and movableinto an operatingposition in said pump receiver wherein it is seated onV said tem for awell, the combination of: supply, return and production tubings set inthe well and respectively adapted to convey operating fluid downwardlyinto the well from the surface, spent operating fluid upwardly in thewell to the surface and fluid produced by the well upwardly therein tothe surface, two of said tubings being inner tubings disposed within thethird; a tubular pump receiver connectedl to the lower ends of saidtubings in alignment with one of said inner tubings, said pump receivercommunicating at its upper end with said one inner tubing and-havingsubstantially the same internaldiameter as said one inner tubing, andsaid pump receiver having passages which provide fluid communicationbetween the other of said inner tubings and said pump receiver, betweenthe outer of said tubings and said pump receiver and between the Welland said pump receiver; a pump seat carried by said pump receiver at thelower end thereof and in alignment therewith; a fluidoperated, free pumpmovable in said one inner tubing and movable into an operating positionin said pump receiver wherein it is seated on said pump seat, said pumphaving an intake, an exhaust, an inlet and an outlet which communicatewith said supply tubing, said return tubing, the well and saidproduction tubing, respectively, when said pump is in said operatingposition; sealing devices for normally preventing direct flow of fluidbetween said tubings and the well by way of said pump receiver when saidpump is in said operating position; a chamber in said pump receiverbetween said pump seatand said pump; andpassage means providing fluidcommunication between said chamber and one of said tubings other thansaid one inner tubing.

'7. In a closed, duid-operated, free-pump system for a well, thecombination of: supply, return and production tubings set in the welland respectively adapted to convey operating iiuid downwardly into thewell from the surface, spent operating uid upwardly in the well to thesurface and fluid produced by the well upwardly therein to the surface,two of said tubings being inner tubings disposed within the third; atubular pump receiver connected to the lower ends of said tubings inalignment with one of said inner tubings, said pump receivercommunicating at its upper end with said one inner tubing and havingsubstantially the same internal diameter as said one inner tubing, andsaid pump receiver having passages which provide fluid communicationbetween the other of said inner tubings and said pump receiver, betweenthe outer of said tubings and said pump receiver and between the welland said pump receiver; a pump seat carried by said pump receiver at thelower end thereof and in alignment therewith; a fluid-operated, freepump movable in said one inner tubing and movable into an operatingposition in said pump receiver wherein it is seated on said pump seat,said pump having an intake, an exhaust, an inlet and an outlet whichcommunicate with said supply tubing, said return tubing, the well andsaid production tubing, respectively, when said pump is in saidoperating position; sealing devices for normally preventing direct flowof Iiuid between said tubings and the well by way of said pump receiverwhen said pump is in said operating position; a chamber in said vpumpreceiver between said pump seat and said pump;- passage means providingfluid communication between said chamber and one of said tubings other'than said one inner tubing; and another sealing device for normallypreventing flow of fluid between said passage means and said productiontubing.

8. A closed system as set forth in claim 7 whereinr said other sealingdevice comprises a spring-loaded valve in said passage means.

9. Aclosedsystem as set forth in claim '7 wherein said other sealingdevice comprises an annular sealing eler'nent positionable between saidpump and said pump receiver.

10. In a closed, fluid-operated, free-pump systern for a well, thecombination of supply, return and production tubings set in the well andrespectively adapted to convey operating fluid downwardly into the wellfrom the surface, spent operating fluid upwardly in the well to thesurface and iiuid produced by the well upwardly l therein to thesurface, two of said tubings being innertubings disposed within thethird; means for interconnecting the lower ends of said tubings in fluidcommunication with each other and with the well; a fluid-operated, freepump movable in one of said inner tubings into an operating position atthe lower end thereof, said pump having an intake, an exhaust, an inletand an outlet which communicate with said supply tubing, said returntubing, the well and said production tubing, respectively, when saidpump is in said operating position; means for normally preventing directflow of iuid between said tubings and the well by way of saidinter-connecting means when said pump is in said operating position; andpassage` means communicating with said one inner tubing and with one ofsaid tubings other than said one inner tubing.

11. A closed system as set forth in claim 10 wherein said inner tubingsare disposed within said return tubing.

12. A closed system as set forth in claim 10 wherein said inner tubingsare disposed Within said production tubing.

13. A closed system as set forth in claim 10 wherein said one innertubing is said supply tubing.

14. A closed system as set forth in claim 10 wherein said passage meanscommunicates with said one inner tubing and with said return tubing.

15. A closed system as set forth in claim 10 wherein said supply andreturn tubings are without said production tubing.

16. A closed system as set forth in claim 10 wherein said one innertubing is of larger diameter than the other inner tubing.

17. A closed system according to claim 10 wherein said production tubingis of larger diameter than at least one of the other two tubings.

18. A closed system as dened in claim 10 wherein said production tubingis of larger diameter than either of the other two tubings.

19. A closed system according to claim 10 wherein said inner tubings aredisposed side-byside within the outer tubing.

20. A closed system as set forth in claim 19 wherein said one innertubing and the other inner tubing are said supply vtubing and saidproduction tubing., respectively, f

21. A closed system asset forth in claim 10 wherein said inner tubingsare disposed side-byside within the outer tubing, said one-inner tubingand said' other inner tubing being said supply tubing and said returntubing, respectively.

22. In a closed, fluid-operated, free-pump system for a well, thecombination of: supply, return and production tubings set in the welland respectively. adapted to convey operating fluid downwardly into thewell from the surfacespent operating iiuid Vupwardly in the well to thesurface and fluid produced by the well upwardly therein to the surface,said supply tubing and one of the others of said tubings being disposedside-by-side within the third tubing; a tubular pump receiver at thelower end of and aligned with said supply tubing, said pump receiverbeing connected to the lower ends of ,said tubings and being in fluidcommunication with said tubings and with the well;l a pump seat carriedby said pump receiver and disposed at the lower end thereof inalignmenttherewith; a duid-operated, free-pump Vmovable. in said-supplytubing and movable into anoperatingvposition in said pump receiverwherein itis seated-,onsaid pump seat, said pumphaving an intake,v anexhaustan inlet and anoutlet which communicate with said supply tubing,said return tubing, the well and said production tubing, respectively,whensaid pump is in said operating. position; means for normallypreventing direct iiow oivi'luid, between said tubing. and the wellthrough` said pump receiver whensaid pump is in saidvopeiating position;and ,passage means communicating with one of said tubings otherthanusaidsupply tubing and with said receiver abovefsaidpump seat.

23. A vclosed y.system asset forth in claim 22 whereinV said passagemeans.- cornmunicates with said return. tubing. and-wherein said meansfor preventing directiiow comprises a sealing device for normallypreventing fluid flow from said return tubingA to said productionAtubing when said pump is in said operating position.

24. A closed'system as set forth `in claim 22 wherein said supply andproduction tubings are disposed side-by-side within said return tubing.

25; A closed system as set Yforth Vin claim 22 wherein said supply andreturnytubings are disposed side-by-sidey with said production tubing.

26,-A closed system-as A,set forth in claim 22 wherein said supplytubing is of larger diameter thanronev of1 the other two tubings.

27.A closed System'asfset forth in claim 22 wherein saidproductiontubing. iS of larger diameter than one of the other twotubings.

28. Ina closed, fluid-operated, free-pump system for a wellythecombina-tion of: supply, return and production tubing set-in the welland respectively adapted .to-convey operating fluid downwardly into theWellfrom the surface, spent operating fluid ,upwardly inthe well to thesurface andi-duid produced by the well upwardly therein-tothe surface,said supply tubing and one oitheother tubing` being disposed side-bysidewithin/the third tubing; a tubular pump receiver Vat the lower end ofand aligned with said supply Vtubing, said pump receiver being connectedto the lower ends ,of said tubings ih iuid ,communication therewith andbeing in duid communicationV with the well; a fluidoperated, free pumpmovable in said supply tubing -into an operating position in said pumpreceiver, said pump having an intake, an exhaust below said intake, anoutlet below said exhaust and an inlet below said outlet, said intake,said exhaust, said inlet and said outlet respectively communicating withsaid supply tubing, said return -tubing,- the well and said productiontubing when said pump is in said operating position; an annular sealingelement carried by said pump intermediate said intake and said exhaustand pump is in said noperatingposition; another ansaid pump receiver ata point which is intermediate said other annular sealingr element andsaid sealing means when said `pump is insaid operating position, saidsystem includingr a sealing device for normally preventingiiow throughksaid passage fromsaid return'ftubingto said production tubing whensaid'pump is in saidv operating position, said sealing device comprisaspring-loaded valvejin saidpassage.

30. A closed system accordingto claim 22 including a passagecommunicating at one end with said return tubing and at its other endwith sai`l pump receiver at a point'which is intermediate said otherannular sealing element and said sealing means when said pump is in saidoperating position, said system including a sealing device for normallypreventing flow through said passage from said return tubing to saidproduction tubing when said pump is in said operating position, saidsealing device comprising an annular sealing element carried by said pupbelow said outlet and engageable with said pump receiver.

31. A closed system as set forth in claim l wherein said third tubing isthe casing of the well.

32. In a closed, duid-operated, free-pump sys- Y tem, the combinationof: a primary tubing. and a pair of secondary tubings set in the wellwith one of said secondary tubings enclosing the other or said secondarytubings and said primary tubing, said primary tubing being of a size toreceive a fluid-operated, free pump and providingl for movement of thepump between an ,operating position "at the lower end of said primarytubing and. the surface; lower ends of said tubings, saidinterconnecting means having passage means providing fluidVcommunication between one of said secondary tubings and said primarytubing and having passage means providingy fluid communication betweenthe other of said secondary tubings and said primary tubing; and inletmeans connected to said primary tubing and havinga passage providing uidcommunication between the well and said primary tubing, said inlet meanshaving means for preventing flow of uid from said primary tubing intothe well through said passage.

CLARENCE J. COREE-LY.

REFERENCES CITED The following references are of record in the ile ofthis patent:

Number Name Date 1,616,773 Warren Feb.A 8, 1927 1,630,902 Parrish May31, 192'? 1,765,921 Joy June 2 4, 1930 2,100,560 Kennedy Nov. 30, 19372,230,830 Coberly Feb.- 4, 1941 2,277,181 Zuck Mai-.24, 1942 2,338,903Coberly Jan. l1, 194e means vinterconnecting the.

